‘Vanished’ Sri Lankan Dwarf Toad Sighted

Until now, if you wanted to catch a glimpse of the Sri Lankan Kandyan dwarf toad (Adenomus kandianus), you had to turn to the history books.

The warty, yellow-bellied amphibian has been gone for more than a century, first discovered in a freshwater stream in Sri Lanka in 1872 and last seen in 1876. Exhaustive surveys since then have turned up nothing.

But during a 2009 effort at cataloguing the region’s forests, which claim more extinct amphibians than any other nation, scientists trekking through the rugged 22,380-hectare Peak Wilderness Sanctuary one night noticed four unusual toads on rocks in a fast-flowing stream.

They recorded characteristics of the toads such as size, shape, feet webbing, and skin texture and collected one of the animals to study further. Comparison of the toad with descriptions and specimens of Adenomus kandianus at the British Museum matched, and the toad’s physical characteristics and genetics failed to match any other known toad.

A second trip to the area yielded discovery of more than 100 of the toads in an area of 200 square meters, the scientists report this month in Zootaxa.

The toad’s small habitat range and similar appearance to a more common amphibian — the torrent toad (Adenomus dasi) — are likely what helped it elude scientists for so long.

While it will no longer be considered extinct, the Kandyan dwarf toad will still be endangered due to the small number that was found and the increasing human encroachment into Sri Lankan forests.

This story provided by ScienceNOW, the daily online news service of the journal Science.